Sat PREFACE. 
It was originally intended that the general account 
should have been a joint production, each of us con- 
tributing his part. There were difficulties, however, 
in the way of this arrangement. We were all fully 
occupied with other matters, and the amount of 
communication and correspondence between us, re- 
quired to carry out the plan of joint authorship, 
seemed likely to prove a cumbrous complication. 
It was therefore decided that guoad the popular 
exposition I should take upon myself the office of 
‘reporter,’ and thus it comes about that I am indi- 
vidually and solely responsible for the opinions and 
statements contained in this book, save where they 
are included within quotation marks, or their sources 
otherwise acknowledged. 
Since we began these deep-sea investigations, 
inquiries have come in from all quarters, both at 
home and abroad, as to the implements and methods 
which we employ. To supply the desired informa- 
tion, I have described, in detail, the processes both 
of sounding and dredging; and I hope that the 
special chapters, on these matters—the result of 
considerable experience—may be found useful to 
beginners. 
I pretend to no special knowledge of physics, and 
I should have greatly preferred confining myself to 
the domain of Biology, my own proper province ; 
but certain physical questions raised during our late 
explorations have so great importance in relation to 
